Support network::ErrorReason::BLOCKED_BY_CLIENT for inspector with network service enabled.

This change makes it so that when client code of the devtools protocol sets the
particular ErrorReason BLOCKED_BY_CLIENT, we capture that it's devtools
(also known as inspector int he code) which blocked the request. We then make
this available via the devtools protocol also that the client may distinguish
resource loads blocked by this particular reason.

Bug: 838291
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Id3b4b9b96ae15f31cb1170d5d6e028b6da05affe
Reviewed-on: https://chromium-review.googlesource.com/1035091
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559623}
22 files changed